The application generally relates to a method of sealing electric motor terminals. The application relates more specifically to a method and apparatus for sealing connections within a conductive environment.
Ammonia is a common, naturally occurring compound in the environment that breaks down naturally into hydrogen and nitrogen. Ammonia refrigeration is a cost effective and energy efficient method of processing and storing frozen and unfrozen foods. Ammonia refrigeration is also used in the chemical industry. Recently, air conditioning has been provided by ammonia refrigeration systems in office buildings, parks, and small buildings such as convenience stores.
Ammonia is electrically conductive and corrosive to many materials, e.g., copper wire used in high efficiency electric motors. Electrical connections, e.g., motor terminations of multiple conductors, which are exposed to ammonia in the environment, can present a risk of short circuit or other failure. Electrical conductors must be electrically insulated and sealed from ammonia vapor or liquid.
An example of a current motor connection arrangement is shown in FIG. 4. Lead wires 12 are soldered or crimped in a cap portion 28. The cap portion is then inserted into a recessed stub portion 29 attached to one end of a stud member 26. Stud member 26 may also include a hexagonal nut portion 27 to provide a surface for applying a wrench, for tightening threads on the stud member 26. An insulator board may be attached to stud member 26 for mounting stud member 26 to the compressor or motor housing 116. The lead wire terminations 12 in cap portion 28 are not insulated and would short circuit if exposed, e.g., to a conductive gas atmosphere or wet environment.
The innovation provides a method to make connections that electrically insulates the conductors while sealing out ammonia vapor or liquid. Currently the common process used for connecting electrical terminals in semi-hermetic compressors is stripping and soldering copper wires into a cap, then inserting the cap into a stub and crimping the cap. There is no provision made for insulating the electrical terminals and conducting parts, as the conventional refrigerants are non-conducting and thus pose no risk of short-circuiting exposed terminals.
What is needed is a method and device for sealing motor terminals in a semi-hermetic compressor using a conductive refrigerant, e.g., ammonia.
Intended advantages of the disclosed systems and/or methods satisfy one or more of these needs or provide other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs.